High Tech Results with a Low Tech BNR Upgrade
Dan Hingley, P. E.Aqua Virginia, Inc.May 9, 2019
2019 VW EA Education Sem inar
2
• Aqua Am erica (N YSE: W TR)
• Founded in 1886 (132 years old)
• O ne of the largest publicly traded
utilities in the USA
• O ver 1,600 em ployees
• O ver one m illion custom ers
• 225 M GD W ater Production
OPERATING IN 8 STATES
Aqua Am erica Highlights
3
• O perations in 1/3 of
Virginia counties
• 80,000 custom ers
• 190 water system s
• 8 wastewater treatm ent
plants
Aqua Virginia O perations
4
• Lake Monticello HOA owned system before selling to AquaSource in 1998
• Failed manholes and piping caused wastewater overflows into the lake
• Facility placed under a consent order for significant wastewater system issues in 2003
• HOA sold the system to AquaSource in 1998
• Aqua America purchased in 2003
• Consent Order lifted after significant capital investment and demonstrated improvement
Lake M onticello Background
5
• 4,625 WASTEWATER CONNECTIONS
• 66 MILES OF WASTEWATER MAINS
• 2,075 MANHOLES
• 54 LIFT STATIONS
Lake M onticello W astewater System
Flow Tracking
6
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Flow
, MGD
Design Flow 95% Design Flow Monthly Avg. Flow
0.775 MGD UPGRADE
Facility Upgrade O ption
7
• Estimated Cost ‐ $7M (2008)
• Stringent Effluent Limitations
Flow Tracking
8
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Flow
, MGD
Design Flow 95% Design Flow Monthly Avg. Flow 3+ mos. At 95%
95% CAPACITY REO PENER
9
A written notice and a plan of action for ensuring continued compliance with theterms of this permit shall be submitted to the DEQ‐Valley Regional Office whenthe monthly average influent flow to the wastewater treatment facility reaches95 percent of the design capacity authorized in this permit for each month of anythree consecutive month period. The written notice shall be submitted within 30days and the plan of action shall be received at the DEQ‐Valley Regional Officeno later than 90 days from the third consecutive month for which the flowreached 95 percent of the design capacity. The plan shall include the necessarysteps and a prompt schedule of implementation for controlling any current orreasonably anticipated problem resulting from high influent flows. Failure tosubmit an adequate plan in a timely manner shall be deemed a violation of thispermit.
Facility Upgrade O ption
10
• Estimated Cost ‐ $7M (2008)
• Stringent Effluent Limitations
W W TP Perform ance
11
0
5
10
15
20
25
30
35
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
2014 2015 2016 2017 2018
TSS, m
g/L
TOTAL SUSPENDED SOLIDS
EFFLUENT PERMIT LIMIT
W W TP Perform ance
12
0
5
10
15
20
25
30
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
2014 2015 2016 2017 2018
CBOD, m
g/L
CARBONACEOUS BOD
Avg. Monthly CBOD, mg/L CBOD Permit Limit, mg/L
I&I Rehabilitation O ption
• Investigate– Visual inspection of m anholes (400, internal and external)
– Stream crossing inspections
– Flow m onitoring at lift stations (34 system s installed)
– CCTV inspection of m ains (8.8 m iles)
• Rehabilitate– Repaired 115 m anholes
– CIPP of ~3,000 LF of m ain
• Capital Cost of ~ $155,000
13
Flow Reduction
14
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
2014 2015 2016 2017 2018
Flow
, MGD
WWTP Flow, MGD Design Flow, MGD 95% Design Flow, MGD
Sept. 25, 2015 ‐ Dec. 31,201617.8 inches of Precipitation
Apr. 1, 2018 ‐ June 30, 201822.6 inches of Precipitation
15
$‐
$20,000
$40,000
$60,000
$80,000
$100,000
$120,000
$140,000
$160,000
$180,000
2011 2012 2013 2014 2015 2016 2017 2018
Cred
it Co
st
N Credits P Credits Member Fee
Nutrient Credit Exchange
Expense Reducing (8:1) Projects in Virginia
16
Year Approved Type of Reduction Project
2016 Com m unication Replace phone lines with Radio for Com m unication
2016 Power Lake Land'orW W TP DO Setpoint Control
2017 Nutrients Lake M onticello Nitrogen Reduction Project
2018 W ater Re-use Lake M onticello W W TP Clarifier Spray W ater Source Conversion
2018 Purchased W ater M ayfield Farm s W ell Replacem ent
2018 M aintenance Captain's Cove In-house Grass Cutting
2019 Power Lake M onticello W W TP Equalization Basin Replacem ent M ixing System
2019 Power Lake Land'O rLift Station M ixing
Existing Process
17
AER DIG
Screen UV
Rivanna River
SCL
RAS
EQB
Centrifuge
LimeAER
Existing Process
18
• High operating expenseso Nutrient credits ‐ $155,000o Aeration Energy ‐ $71,000o Chemicals ‐ $48,000
Upgrade O ption
19
Upgrade O ption
20
• High Capital Cost o $8.5M (2019)
• Stringent Effluent Limitations
Retrofit O ption
21
AER DIG
Screen UV
Rivanna River
INT. AER SCL
RAS
ANX AERAER/ ANXANREQB
Centrifuge
Lime
Process Design
22
Retrofit O ption
23
• Low Capital Costo < $200,000
• Reduced operating expenseso Nutrient credits ‐ $20,000o Aeration Energy ‐ $50,000o Chemicals ‐ $14,000
Project com ponents
24
Component Technology Responsibility Cost
Air Supply Header Mods.
SST pipe & accessories, MOVs
Design: In‐houseConstruction: Contractor
$81,400
Mixing System Large bubble Design: In‐house (HRSD concept)Construction: In‐house
$24,400
Diffuser Mods. Membrane Diffusers
Design: In‐houseConstruction: In‐house
$16,600
Baffles Membrane Curtains
Design: In‐house (worked w/vendor)Construction: In‐house
$37,600
Σ $160,000
Before Retrofit
25
After Retrofit
26
Interm ittent Aeration Controls
27
Interm ittent Aeration Controls
28
AB 1 CLOSE DELAY
AB 1 CLOSE DURATION
AB 2 CLOSE DELAY
AB 2 CLOSE DURATION
Timer SettingAB 1 close delay, min 0.5AB 1 close duration,min 20.0AB 2 close delay, min 0.5AB 2 close duration, min 20.0
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100 120
% of Total Airflow
Time, minutes
AB 1 AB 2
Interm ittent Aeration Controls
29
Timer SettingAB 1 close delay, min 10.0AB 1 close duration,min 20.0AB 2 close delay, min 10.0AB 2 close duration, min 20.0
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100 120
% of Total Airflow
Time, minutes
AB 1 AB 2
Interm ittent Aeration Controls
30
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
Jan‐19 Feb‐19 Mar‐19 Apr‐19 May‐19 Jun‐19
TN, m
g/L
Extended Air
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
Jan‐19 Feb‐19 Mar‐19 Apr‐19 May‐19 Jun‐19
TN, m
g/L
Extended Air
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
Jan‐19 Feb‐19 Mar‐19 Apr‐19 May‐19 Jun‐19
TN, m
g/L
Extended Air Target
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
Jan‐19 Feb‐19 Mar‐19 Apr‐19 May‐19 Jun‐19
Efflu
ent T
N, m
g/L
Extended Air Construction BNR Retrofit Target
31
Prelim inary Results
32
‐
10,000
20,000
30,000
40,000
50,000
60,000
70,000
80,000
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
Nitrog
en Loa
d, lbs/yr
Discharged WLA
FORECAST
33
$‐
$20,000
$40,000
$60,000
$80,000
$100,000
$120,000
$140,000
$160,000
$180,000
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
Cred
it Co
st
N Credits P Credits Member Fee
FORECAST
34
0
500
1,000
1,500
2,000
2,500
3,000
3,500
Jan‐17 May‐17 Sep‐17 Jan‐18 May‐18 Sep‐18 Jan‐19 May‐19
Lime Ad
ditio
n, lb
/day
35
0
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
Jan‐17 May‐17 Sep‐17 Jan‐18 May‐18 Sep‐18 Jan‐19 May‐19
Power Con
sumption, kWh/da
y
Anticipated Expense Reductions
36
Expense Type Historical Cost Projected Cost Savings, $ Savings, %
Nutrient Credits $155,000 $20,000 $135,000 87%
Aeration Energy $71,000 $50,000 $21,000 30%
Alkalinity $48,000 $14,000 $34,000 70%
Depreciation $0 $11,000 ($11,000) ‐
Σ $287,000 $101,000 $186,000 ‐
• 1.8% reduction in total O&M expense• 6.1% reduction in wastewater O&M expense
Q uestions?
37
38
‐
1,000
2,000
3,000
4,000
5,000
6,000
7,000
8,000
2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
Phosph
orus Loa
d, lb
s/yr
Discharged WLA
39
$‐
$20
$40
$60
$80
$100
$120
$140
$160
Jan‐17 May‐17 Sep‐17 Jan‐18 May‐18 Sep‐18 Jan‐19 May‐19
Lime Ad
ditio
n, $/day
40
$‐
$50
$100
$150
$200
$250
$300
$350
Jan‐17 May‐17 Sep‐17 Jan‐18 May‐18 Sep‐18 Jan‐19 May‐19
Power Con
sumption, $/day
EXCESS I/I
41
0.000
0.100
0.200
0.300
0.400
0.500
0.600
0.700
0.800
0.900
1.000Oct
Nov Dec
Jan
Feb
Mar Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar Apr
May Jun Jul
2015 2016 2017 2018
WATER CONSUMED vs WW TREATED
Average Water Consumed, MGD Average WW Treated, MGD
53% I/I
42
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.90
1.00Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
Mar
Apr
May Jun Jul
Aug
Sep
Oct
Nov Dec
Jan
Feb
2014 2015 2016
WWTP
Flow, M
GD
WWTP Flow, MGD Design Flow, MGD 95% Design Flow, MGD
~ 50% I&I
Flow Tracking
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